How to Avoid an Excessive DOM Size on Your Shopify Store

How to Avoid an Excessive DOM Size on Your Shopify Store

How to Avoid an Excessive DOM Size on Your Shopify Store

Having an optimized and efficient online store is critical for the success of any eCommerce venture. One common issue that impedes website performance is an excessive DOM size. So, what exactly is DOM, and how can a large DOM size hurt your store’s performance? In this comprehensive guide, we'll delve into understanding the excessive DOM size problem and provide actionable steps to resolve it specifically for Shopify users.

What is DOM and Why Should You Care?

Understanding the DOM

The Document Object Model (DOM) is an interface that allows programs and scripts to dynamically access and update the content, structure, and style of a document. It represents the page so that programs can change the document structure, style, and content. A large DOM size can lead to several performance issues, especially on eCommerce websites where speed and user experience are crucial.

Why is an Excessive DOM Size Problematic?

  1. Increased Memory Usage: A large DOM can cause excessive memory consumption on browsers, leading to slow performance and potential crashes.
  2. Longer Style Calculations: More elements mean more work for the browser’s rendering engine, which can lead to longer style calculation times and delays in rendering the page.
  3. Costly Layout Reflows: Modifying elements in a large DOM can force the browser to recalculate layout properties, causing multiple reflows which slow down page loading times.

Identifying the Problem: Excessive DOM Size on Your Shopify Store

PageSpeed Insights Report

According to your PageSpeed Insights report, your Shopify store at ManKave Store using the Refresh Theme has a DOM size of 7,244 elements. The report also highlights that having such a large DOM will increase memory usage, cause longer style calculations, and produce costly layout reflows.

Why Does Your Shopify Store Have an Excessive DOM Size?

Common Causes

  1. Complex HTML Structure: The theme of your store might have an overly complicated HTML structure with nested elements that inflate the DOM size.
  2. Third-Party Apps and Plugins: Additional functionalities from third-party apps can inject a lot of elements into the DOM, increasing its size.
  3. Duplicate Elements: Sometimes, elements might be unnecessarily duplicated, contributing to an increased DOM size.
  4. Hidden Elements: Elements that are hidden but not removed also contribute to the DOM size.
  5. Large Navigation Menus: Extensive menus and redundant links in your navigation can add unnecessary DOM elements.

Steps to Avoid an Excessive DOM Size

1. Optimize Theme Code

  • Simplify HTML Structure: Review and simplify the HTML structure of your theme by reducing the depth of nested elements and removing unnecessary tags.
  • Combine CSS and JavaScript Files: Reduce the number of CSS and JavaScript files to minimize the number of script and link tags in the DOM.
  • Lazy Load Images: Implement lazy loading for images to ensure that only images in the viewport are loaded initially.

2. Review and Optimize Third-Party Apps

  • Audit Your Installed Apps: Regularly audit the third-party apps installed on your store. Remove any apps that are not providing significant value or are contributing heavily to the DOM size.
  • Custom Implementations: Where possible, replace third-party app functionalities with custom code that is lighter and more optimized.

3. Clean Up Unnecessary Elements

  • Remove Duplicate Elements: Check for and remove duplicate elements across your site to reduce the DOM size.
  • Prune Hidden Elements: Remove hidden elements that are not required instead of just hiding them using CSS.

4. Optimize Navigation Menus

  • Structure Menus Efficiently: Review the structure of your navigation menus. Combine or minimize menu items where possible without compromising user experience.
  • Use Collapsible Menus: Employ collapsible menus for large navigation elements to keep the initial DOM size smaller.

5. Regularly Monitor DOM Size

  • Use Tools for Inspection: Use browser developer tools or performance tools like PageSpeed Insights to regularly monitor your site’s DOM size. Set benchmarks and aim to stay within them.

FAQ: Common Questions About Excessive DOM Size

  • Q: Can excessive DOM size affect mobile performance?
    • A: Yes, mobile devices, which typically have less processing power and memory than desktops, can struggle more with large DOM sizes, leading to sluggish performance and poor user experience.
  • Q: Are there automated tools to reduce DOM size?
    • A: While there aren’t specific automated tools that can universally reduce DOM size, performance audit tools like Lighthouse, PageSpeed Insights, and browser developer tools can help you identify DOM issues.


Dealing with an excessive DOM size is crucial for maintaining optimal performance of your Shopify store. By understanding the causes and implementing the solutions provided in this guide, you can ensure a smoother, faster, and more user-friendly experience for your customers. Regular monitoring and maintenance are key to continually avoiding excessive DOM size and keeping your store running efficiently.